[FFmpeg-devel] [PATCH] grayalpha pixfmt + support in pngdec

[Baptiste Coudurier]

On 06/03/2010 03:45 AM, Michael Niedermayer wrote:
> On Wed, Jun 02, 2010 at 05:37:36PM -0700, Baptiste Coudurier wrote:
>> On 04/18/2010 03:57 PM, Michael Niedermayer wrote:
>>> On Sun, Apr 18, 2010 at 09:36:22PM +0200, Stefano Sabatini wrote:
>>>> On date Tuesday 2010-04-13 12:21:47 +0200, Michael Niedermayer encoded:
>>>>> On Tue, Apr 13, 2010 at 10:34:48AM +0200, Andreas ?man wrote:
>>>>>> Kostya wrote:
>>>>>>> On Tue, Apr 13, 2010 at 09:33:51AM +0200, Andreas ?man wrote:
>>>>>>>> Michael Niedermayer wrote:
>>>>>>>>> On Mon, Apr 12, 2010 at 09:40:03PM +0200, Andreas ?man wrote:
>>>>>>>>>> Michael Niedermayer wrote:
>>>>>>>>>>> On Mon, Apr 12, 2010 at 10:43:02AM +0200, Andreas ?man wrote:
>>>>>>>>>>>> Hi
>>>>>>>>>>>> +    [PIX_FMT_GRAYALPHA] = {
>>>>>>>>>>>> +        .name = "grayalpha",
>>>>>>>>>>> where does the name grayalpha come from?
>>>>>>>>>> I just didn't come up with anything better.
>>>>>>>>>> Ideas are most welcome.
>>>>>>>>> something that is consistent with existing formats would
>>>>>>>>> be better also what is it calld in the png docs?
>>>>>>>> PNG docs seems to call it "Grayscale with alpha" or "ya".
>>>>>>>> Perhaps "ya" would be a good name then?
>>>>>>> Nej, it obviously stands for "Y(aka luma) + A(alpha)"
>>>>>>> i.e. not so good acronym.
>>>>>>
>>>>>> Kostya suggested "Y400A" on IRC.
>>>>
>>>> I'm not very happy with this name, "4XX" notation only makes sense
>>>> when we have three components, in this case I would have preferred
>>>> something of the kind GRAY8ALPHA8 or GRAYALPHA8 (consistent with
>>>> GRAY8), even YA was not that bad.
>>>
>>> GRAY*ALPHA* is inconsistent with the existing naming and gray8 is quite
>>> alone and the exception, not a good example to copy.
>>>
>>>
>>>>
>>>> Not that I consider this a big issue, we will eventually fix the names
>>>> at the next major bump.
>>>
>>> The naming is good and reasonable consistent. To change it at the next maj
>>> ver
>>> bump there needs to be a problem in the existing naming and a better
>>> naming and
>>> consensus amongth the devels that the new is better and not just the
>>> yearly
>>> bikeshed style. Because every such change means everyone will have to
>>> update
>>> their applications and this is a lot of work when one considers how many
>>> applications there are. Not to mention the ones that try to support
>>> differnent
>>> lav* versions
>>>
>>
>> I need to revive this thread since I've come up with a file that I want
>> supported.
>>
>> I disagree, Y400A is a very bad name since the gray plane is coded using
>> 0-255 and IMHO is not really similar to a Y plane IMHO in the YUV sense, if
>> you want to call it Y then YJ400A at least.
>
> the luma range, really is indicated by AVCodecContext.color_range
> the J pixel formats are deprecated.

Then mark them as so, and start changing the code, because I would 
personally not remove something that has been in the code so long ;)

> Thats mainly because there are far too many yuv variations than what
> could be indicated by a few pixel formats.

Well, I don't know about that.
Anyway, that's good, you don't want YJ, so you are ok with GRAY8A ?
The base point being that GRAY8 is not Y400 IMHO.

-- 
Baptiste COUDURIER
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